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Impact of doping profiles on the formation of laser-active centers in bismuth-doped GeO_(2)–SiO_(2)glass fibers

photonics Research 2024年第2期12卷 260-270页

作者： SERGEY ALYSHEV alexander VAKHRUSHEV ALEKSANDR KHEGAI ELENA FIRSTOVA KONSTANTIN RIUMKIN MIKHAIL MELKUMOV LYUDMILA ISKHAKOVA ANDREY UMNIKOV SERGEI FIRSTOV prokhorov General physics Institute of the Russian Academy of Sciences Dianov Fiber Optics Research Center119333 MoscowRussia Devyatykh Institute of Chemistry of High-purity Substances of the Russian Academy of Sciences 603951 Nizhny NovgorodRussia

Multi-wavelength-band transmission technology based on the exploitation of the extended spectral region is considered as a potential approach to increase the transmission capacity in the deployed fiber-optic communication *** development of optical amplifiers operating in the O-,E-,S-,and U-telecom bands is an extremely important challenge for the successful implementation of this ***-doped fibers are of increasing interest as gain materials,which can be used to provide broadband amplification in the mentioned telecom *** is due to the ability of Bi ions incorporated into glass network to form bismuth active centers(BACs)with specific optical properties,which are primarily determined by the glass *** this work,the impact of the doping profiles of both Ge atoms as glass modifiers and Bi ions on the BACs formation is studied using a series of bismuth-doped fibers fabricated by the modified chemical vapor deposition(MCVD)*** Bi-to-BACs conversion efficiency in various spatial regions of the studied samples is *** is turned out that for high-Bi concentration regions,the conversion efficiency is very low(less than 10%).In addition,the relationship of the conversion efficiency to the distribution of Bi ions and/or Ge atoms is ***,a continuous-wave laser at 1.46μm with a record slope efficiency of 80%is demonstrated using a Bi-doped fiber with confined doping profile,where the Bi-to-BACs conversion efficiency is 35%.This paper provides new information which might help to facilitate understanding of the features of Bi-doped fibers and their potentially achievable characteristics.

关键词： fiber fibers bismuth

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Structural and chemical transformations of CuZn alloy nanoparticles under reactive redox atmospheres:An in situ TEM study

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Nano Research 2024年第7期17卷 6265-6273页

作者： Shengnan Yue Qian Li Chaobin Zeng alexander Klyushin Ramzi Farra Marc-Georg Willinger Xing Huang College of Chemistry Fuzhou UniversityFuzhou 350108China Qingyuan Innovation Laboratory Quanzhou 362801China Hitachi High-Tech Scientific Solutions(Beijing)Co. Ltd.Beijing 100015China MAX IV Laboratory Lund UniversityBox 11822100 LundSweden Department of Inorganic Chemistry Fritz-Haber Institute of Max Planck SocietyBerlin 14195Germany Department of Chemistry Technical University of MunichGarching 85748Germany

Alloying metals to form intermetallics has been proven effective in tuning the chemical properties of metal-based ***,intermetallic alloys can undergo structural and chemical transformations under reactive conditions,leading to changes in their catalytic *** and understanding these transformations are crucial for establishing relevant structureperformance relationships and for the rational design of alloy-based *** this work,we used CuZn alloy nanoparticles(Nps)as a model material system and employed in situ transmission electron microscopy(TEM)to investigate the structural and chemical changes of CuZn Nps under H_(2),O_(2)and their *** results show how CuZn Nps undergo sequential transformations in the gas mixture at elevated temperatures,starting with gradual leaching and segregation of Zn,followed by oxidation at the Np *** remaining copper at the core of particles can then engage in dynamic behavior,eventually freeing itself from the zinc oxide *** structural dynamics arises from an oscillatory phase transition between Cu and Cu_(2)O and is correlated with the catalytic water formation,as confirmed by in situ mass spectrometry(MS).Under pure H_(2)or O_(2)atmosphere,we observe different structural evolution pathways and final chemical states of CuZn Nps compared to those in the gas *** results clearly demonstrate that the chemical state of alloy Nps can vary considerably under reactive redox atmospheres,particularly for those containing elements with distinct redox properties,necessitating the use of in situ or detailed ex situ characterizations to gain relevant insights into the states of intermetallic alloy-based catalysts and structure-activity relationships.

关键词： In situ transmission electron microscopy(TEM) CuZn alloy structural and chemical transformations redox atmosphere

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High-speed performance self-powered short wave ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)

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Journal of Semiconductors 2024年第4期45卷 56-62页

作者： Aleksei Almaev alexander Tsymbalov Bogdan Kushnarev Vladimir Nikolaev Alexei pechnikov Mikhail Scheglov Andrei Chikiryaka petr Korusenko Research and Development Center for Advanced Technologies in Microelectronics National Research Tomsk State UniversityTomsk 634050Russia Fokon LLC Kaluga 248035Russia Department of Semiconductor Electronics and physics of Semiconductors National University of Science and Technology MISISMoscow 119049Russia perfect Crystals LLC Saint Petersburg 194223Russia Department of Solid-State Electronics Saint Petersburg State UniversitySaint Petersburg 199034Russia Department of physics Omsk State Technical UniversityOmsk 644050Russia

High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with pt contacts were demonstrated and their properties were studied in ***κ(ε)-Ga_(2)O_(3)layers were deposited by the halide vapor phase epitaxy on patterned GaN templates with sapphire *** spectral dependencies of the photoelectric properties of struc-tures were analyzed in the wavelength interval 200-370 *** maximum photo to dark current ratio,responsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 ***.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,respectively,at a wavelength of 200 nm and an applied voltage of 1 *** enhancement of the photoresponse was caused by the decrease in the Schottky barrier at the pt/κ(ε)-Ga_(2)O_(3)interface under ultraviolet *** detectors demon-strated could functionalize in self-powered mode due to built-in electric field at the pt/κ(ε)-Ga_(2)O_(3)*** responsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero applied voltage were 0.9 mA/W and 0.46%,*** rise and decay times in self-powered mode did not exceed 100 ms.

关键词： κ(ε)-gallium oxide solar-blind shortwave ultraviolet radiation detectors self-powered operation mode

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Convergent Data-Driven Regularizations for CT Reconstruction

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1342-1368页

作者： Samira Kabri alexander Auras Danilo Riccio Harmut Bauermeister Martin Benning Michael Moeller Martin Burger Helmholtz Imaging Deutsches Elektronen-Synchrotron DESYNotkestr.8522607 HamburgGermany Institute for Vision and Graphics University of SiegenAdolf-Reichwein-StraBe 2a57076 SiegenGermany School of Mathematical Sciences Queen Mary University of LondonMile End RoadLondon E14NSUK The Alan Turing Institute British Library96 Euston RdLondon NW12DBUK Fachbereich Mathematik Universitat HamburgBundesstrasse 5520146 HamburgGermany

The reconstruction of images from their corresponding noisy Radon transform is a typical example of an ill-posed linear inverse problem as arising in the application of computerized tomography(CT).As the(naive)solution does not depend on the measured data continuously,regularization is needed to reestablish a continuous *** this work,we investigate simple,but yet still provably convergent approaches to learning linear regularization methods from *** specifically,we analyze two approaches:one generic linear regularization that learns how to manipulate the singular values of the linear operator in an extension of our previous work,and one tailored approach in the Fourier domain that is specific to *** prove that such approaches become convergent regularization methods as well as the fact that the reconstructions they provide are typically much smoother than the training data they were trained ***,we compare the spectral as well as the Fourier-based approaches for CT-reconstruction numerically,discuss their advantages and disadvantages and investigate the effect of discretization errors at differentresolutions.

关键词： Inverse problems Regularization Computerized tomography(CT) Machine learning

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parallelizable Calculation of Observables Values on Analog Quantum Computer

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Journal of Applied Mathematics and physics 2024年第7期12卷 2400-2406页

作者： alexander Soiguine SOiGUINE Quantum Computing Aliso Viejo USA

The superiority of hypothetical quantum computers is not due to faster calculations but due to different schemes of calculations running on special hardware. The core of quantum computing follows the way a state of a quantum system is defined when basic things interact with each other. In conventional approach it is implemented through tensor product of qubits. In the geometric algebra formalism simultaneous availability of all the results for non-measured observables is based on the definition of states as points on three-dimensional sphere.

关键词： Geometric Algebra Wave Functions Entanglement Maxwell Equations Three-Dimensional Sphere States Observables Measurements GpU Multithreading OpenCL

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A new look at the first dinosaur discovered in Antarctica:reappraisal of Antarctopelta oliveroi(Ankylosauria:parankylosauria)

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Advances in polar Science 2024年第1期35卷 78-107页

作者： Sergio SOTO ACUÑA alexander OVARGAS Jonatan KALUZA Red paleontológica U-Chile Departamento de BiologíaFacultad de CienciasUniversidad de ChileÑuñoa 7800003Chile Escuela de Geología Facultad de CienciasIngeniería y TecnologíaUniversidad MayorProvidenciaSantiago 7500994Chile Fundación de Historia Natural Félix de Azara Universidad MaimónidesBuenos Aires C1405Argentina Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) Buenos Aires C1425FQBArgentina

The first dinosaur discovered in the Antarctic continent was the ankylosaur Antarctopelta oliveroi in the ***,since then several hypotheses of phylogenetical relationships have been proposed because these have been depended on how the skeletal remains have been *** main obstacle for clarifying its phylogenetic position is that many portions of the skeleton remain unknown,in addition to the presence of unknown characters in typical *** an ankylosaurid,nodosaurid,or even a chimaera,a recent proposal based on mostly complete material of a new ankylosaur from Chilean patagonia provided support for a novel phylogenetic hypothesis:Antarctopelta and other southern ankylosaurs are an early branching clade,the parankylosauria,whose origin probably dates to the Late *** the light of this new view,a redescription of the available skeletal remains is provided together with a new reconstruction of the first Antarctic dinosaur known to the science community.

关键词： Antarctic peninsula Biogeographic Weddellian province parankylosauria Antarctopelta

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Quantum Computingvia Entanglement in Geometric Algebra Approach

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Journal of Applied Mathematics and physics 2024年第2期12卷 445-457页

作者： alexander Soiguine SOiGUINE Quantum Computing Aliso Viejo USA

The superiority of hypothetical quantum computers is not due to faster calculations but due to different scheme of calculations running on special hardware. At the same time, one should realize that quantum computers would only provide dramatic speedups for a few specific problems, for example, factoring integers and breaking cryptographic codes in the conventional quantum computing approach. The core of quantum computing follows the way a state of a quantum system is defined when basic things interact with each other. In the conventional approach, it is implemented through the tensor product of qubits. In the suggested geometric algebra formalism simultaneous availability of all the results for non-measured observables is based on the definition of states as points on a three-dimensional sphere, which is very different from the usual Hilbert space scheme.

关键词： Geometric Algebra Wave Functions Entanglement Maxwell Equations Three-Dimensional Sphere

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Aspirin interruption before neurosurgical interventions:A controversial problem

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World Journal of Cardiology 2024年第4期16卷 191-198页

作者： alexander Kulikov Anton Konovalov pier paolo pugnaloni Federico Bilotta Department of Anesthesiology Burdenko National Medical Research Center of NeurosurgeryMoscow 125047Russia Department of Vascular Neurosurgery Burdenko National Medical Research Center of NeurosurgeryMoscow 125047Russia Department of Anesthesiology Critical Care and Pain MedicineUniversity of Rome“Sapienza”Rome 00161Italy

Aspirin is widely used for primary or secondary prevention of ischemic *** the same time,chronic aspirin consumption can affect blood clot formation during surgical intervention and increase intraoperative blood *** is especially important for high-risk surgery,including *** European Society of Cardiology guidelines recommend aspirin interruption for at least 7 d before neurosurgical intervention,but this suggestion is not supported by clinical *** narrative review presents evidence that challenges the necessity for aspirin interruption in neurosurgical patients,describes options for aspirin effect monitoring and the clinical implication of these methods,and summarizes current clinical data on bleeding risk associated with chronic aspirin therapy in neurosurgical patients,including brain tumor surgery,cerebrovascular procedures,and spinal surgery.

关键词： Aspirin Neurosurgery postoperative complications Bleeding risk Brain tumor surgery Cerebrovascular surgery Spinal surgery

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peculiarities of Ethylene polymerization Reactions with Bis(imino)pyridyl Complexes of CoCl_(2) and FeCl_(2)

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Chinese Journal of polymer Science 2024年第4期42卷 492-500页

作者： Laura A.Rishina Yury V.Kissin Svetlana S.Lalayan Artem A.Antonov Vadim G.Krasheninnikov alexander A.Gulin N.N.Semenov Federal Research Center for Chemical physics Russian Academy of Sciences4 Kosygin St.Moscow119991Russia Department of Chemistry and Chemical Biology RutgersThe State University of New Jersey123 Bevier Rd.PiscatawayNJ08854USA Boreskov Institute of Catalysis Russian Academy of Sciences5 Lavrentieva Prosp.Novosibirsk630090Russia

The article describes ethylene polymerization reactions with transition metal catalysts based on complexes of CoCl_(2) and FeCl_(2) with an N,N,N-tridentate ligand 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridine. The complexes are converted into polymerization catalysts by reacting them either with polymethylalumoxane (MAO) or with a combination of Al(C2H5)2Cl and Mg(C4H9)2 at an [Al]:[Mg] ratio of ~3. Both MAO-activated complexes readily polymerize ethylene at 35 ℃ with the formation of linear, low molecular weight polymers with a narrow molecular weight distribution. The same complexes, when activated with the Al(C2H5)2Cl-Mg(C4H9)2 combination, form multi-center catalysts and generate polyethylenes with a broad molecular weight distribution.

关键词： Ethylene polymerization Bis(imino)pyridyl complexes of CoCl_(2)and FeCl_(2) Molecular-weight distribution polymer chain structure

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Effect of autologous serum after amniotic membrane transplantation for persistent corneal ulcers

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International Journal of Ophthalmology(English edition) 2024年第9期17卷 1639-1644页

作者： Rozaliya Hristova petya Yankova Georgi Markov alexander Oscar Yani Zdravkov Department of Ophthalmology Medical University SofiaUniversity Hospital AlexandrovskaSofia 1431Bulgaria Department of Clinical Immunology Medical University SofiaUniversity Hospital AlexandrovskaSofia 1431Bulgaria

AIM:To investigate the effect of adding autologous serum eye drops to the postoperative regime after amniotic membrane transplantation for severe persistent corneal ***:Forty eyes of 40 patients with persistent corneal ulcers were randomly assigned to artificial tears(sodium hyaluronate 0.2%,ATs group,n=20)or autologous serum eye drops(ASEDs,n=20)following treatment with amniotic membrane *** slit lamp images were acquired from all patients before and 30d post *** area with fibrovascular tissue was calculated using Image *** corneal sensitivity was assessed by Cochet-Bonnet aesthesiometry before and one month after *** tissue transparency was assessed with a novel optical ***:Mean age of patients was 61.65±16.47y and 57.3±19.11y in the ATs group and ASEDs group,***-two male and 18 female patients were included in the *** improvement in visual acuity was significantly greater in the ASEDs group(0.14±0.04)than the ATs(0.08±0.04;p=0.00046).Cochet-Bonnet aesthesiometry improved significantly after treatment with a similar rate between *** were no statistically significant differences in the area of postoperative fibrovascular tissue between the two groups(p=0.082).The success rate in the two groups was *** difference in densitometry between the ATs and ASEDs group was statistically significant(p=0.042)with greater reduction from baseline in the ASEDS ***:Autologous serum eye drops can lead to better visual acuity,more stable results and improved densitometry and should be considered in the postoperative care following amniotic membrane transplantation.

关键词： autologous serum amniotic membrane ocular surface persistent corneal ulcer

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